The man, 36, told police that his wife, also 36, noticed a strange taste from a drink she made with Chinese yam powder at home last month.

A police source said the can of Chinese yam powder had been stored in a refrigerator and surveillance camera footage showed the maid, 35, acting suspiciously near the refrigerator. The couple sacked the helper upon seeing it.

The couple then took the can of yam powder to a private laboratory for analysis. The lab results were released on Tuesday, showing there was talcum powder mixed with the yam powder. The man then called police with the information.

Talc-based powder is considered “probably carcinogenic” to people and is in the same category as red meat, according to the Hong Kong Anti-Cancer Society. Talcum powder poisoning can occur if the powder is inhaled or ingested. Symptoms include low blood pressure, difficulty breathing, chest pain, vomiting and even coma in extreme cases.

In Hong Kong, administering any poison or other destructive or noxious substance with intent to injure, aggrieve, or annoy carries a maximum penalty of three years in prison.